The present invention relates to a system for dispensing fluid, such as a liquid diet, from a source of the fluid to at least one delivery station. The present invention also relates to a control valve for use in such a system.
In animal operations, it has been observed that, a liquid diet when offered as a supplement to nursing pigs, has been shown to increase their growth rate. Also, after weaning, animals such as piglets and calves tend to drink substantial amounts of water but eat little solid food. Until the animal more willingly eats solid food, the growth of the animal is slowed due to this increased consumption of water and attendant nutritional deficiency.
To solve this problem and improve growth rate, feeding systems have been developed to deliver liquid diet to one or more delivery stations located, for example, in a farrowing crate. The liquid diet is mixed in a mixer and delivered through a supply line to the delivery stations.
Each delivery station includes a feeder such as a nipple or bowl for providing the diet directly to one or more animals. One or more delivery stations are located in a farrowing crate or pen containing the animals. The liquid diet circulates in the system in response to gravity or a pump. A return line allows the unused fluid to recirculate back to the mixer.
One problem with such liquid diet delivery systems is the buildup of bacteria and other contaminants in the system. Animals such as piglets and calves are particularly susceptible to disease as a result of ingesting these bacteria and contaminants.
Therefore, periodically, as a routine operation of the system, the system must be cleaned. To clean the system, a cleaning solution is conveyed through the system. The mixer is filled with the cleaning fluid and the fluid is pumped through the system, recirculating back to the mixer.
However, during the cleaning operation, unless the delivery stations are isolated from the cleaning solution, animals with access to the delivery stations may be harmed by the cleaning solution. Therefore, flow of liquid in the system between the supply line and the delivery stations must be interrupted whenever cleaning fluid is present in the system.
Liquid diet distribution systems have included manually operated valves located at each delivery station. Before the system cleaning operation, each valve is manually closed to interrupt flow of the fluid in the system to the delivery station. With the valve closed, the delivery station is isolated from the supply line. Cleaning fluid is then circulated in the system without risk to the animals. Following the cleaning operation, each valve is opened and the system may again be used for providing diet, water or other fluid to the animals.
One limitation of such a system is the need for human intervention for operation of the valves. Each valve must be manually turned off before cleaning fluid is circulated in the system. Similarly, each valve must be manually turned on again before the liquid diet may be provided to the individual delivery stations. This manual intervention is burdensome and time consuming, particularly in systems having a large number of delivery stations or delivery stations which are spaced substantial distances apart. Moreover, the requirement of manual intervention in the operation of the system creates the opportunity for error in system operation. One or more valves may not be turned off before circulation of cleaning fluid, allowing the cleaning fluid to be pumped to a delivery station, resulting in possible death of animals. Also, one or more valves may not be turned on after a cleaning operation so that no liquid diet is provided to one or more delivery stations, again resulting in possible death of animals.
Liquid diet delivery systems have included a source such as a bin or tank for storing the diet before delivery. To simplify transportation and storage, diet is preferably concentrated in a liquid or powder form. Therefore, a mixer must be provided for mixing the concentrated diet with a liquid such as water for delivery by the delivery system. However, manual mixing of concentrated diet and water is time consuming and labor intensive. Also, measuring the requisite amounts of concentrated diet and water is susceptible to error.
Accordingly, there is a need for a system for dispensing fluids such as liquid diet to one or more delivery stations. There is a further need for such a system capable of circulating other fluids, such as cleaning fluid, without providing the other fluids to the one or more delivery stations. There is a still further need for such a system including a mixer which automatically combines predetermined amounts of concentrated diet and a liquid such as water.
Still further, there is a need for such a system which will automatically actuate predetermined valves appropriately to ensure that such other fluids as are harmful to animals are not delivered to a delivery station.